Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Nat Cell Biol 2005 Apr 01;74:405-11. doi: 10.1038/ncb1237.
Show Gene links Show Anatomy links

Spinophilin regulates Ca2+ signalling by binding the N-terminal domain of RGS2 and the third intracellular loop of G-protein-coupled receptors.

Wang X , Zeng W , Soyombo AA , Tang W , Ross EM , Barnes AP , Milgram SL , Penninger JM , Allen PB , Greengard P , Muallem S .

Signalling by G proteins is controlled by the regulator of G-protein signalling (RGS) proteins that accelerate the GTPase activity of Galpha subunits and act in a G-protein-coupled receptor (GPCR)-specific manner. The conserved RGS domain accelerates the G subunit GTPase activity, whereas the variable amino-terminal domain participates in GPCR recognition. How receptor recognition is achieved is not known. Here, we show that the scaffold protein spinophilin (SPL), which binds the third intracellular loop (3iL) of several GPCRs, binds the N-terminal domain of RGS2. SPL also binds RGS1, RGS4, RGS16 and GAIP. When expressed in Xenopus laevis oocytes, SPL markedly increased inhibition of alpha-adrenergic receptor (alphaAR) Ca2+ signalling by RGS2. Notably, the constitutively active mutant alphaAR(A293E) (the mutation being in the 3iL) did not bind SPL and was relatively resistant to inhibition by RGS2. Use of betaAR-alphaAR chimaeras identified the 288REKKAA293 sequence as essential for the binding of SPL and inhibition of Ca2+ signalling by RGS2. Furthermore, alphaAR-evoked Ca2+ signalling is less sensitive to inhibition by SPL in rgs2-/- cells and less sensitive to inhibition by RGS2 in spl-/- cells. These findings provide a general mechanism by which RGS proteins recognize GPCRs to confer signalling specificity.

PubMed ID: 15793568
Article link: Nat Cell Biol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: gprc6a ppp1r9b rgs1 rgs16 rgs19 rgs2 rgs4 suclg1